763 research outputs found
USAF solar thermal applications overview
Process heat applications were compared to solar thermal technologies. The generic process heat applications were analyzed for solar thermal technology utilization, using SERI's PROSYS/ECONOMAT model in an end use matching analysis and a separate analysis was made for solar ponds. Solar technologies appear attractive in a large number of applications. Low temperature applications at sites with high insolation and high fuel costs were found to be most attractive. No one solar thermal technology emerges as a clearly universal or preferred technology, however,, solar ponds offer a potential high payoff in a few, selected applications. It was shown that troughs and flat plate systems are cost effective in a large number of applications
Liquid-Gas Phase Transition in Nuclear Equation of State
A canonical ensemble model is used to describe a caloric curve of nuclear
liquid-gas phase transition. Allowing a discontinuity in the freeze out density
from one spinodal density to another for a given initial temperature, the
nuclear liquid-gas phase transition can be described as first order. Averaging
over various freeze out densities of all the possible initial temperatures for
a given total reaction energy, the first order characteristics of liquid-gas
phase transition is smeared out to a smooth transition. Two experiments, one at
low beam energy and one at high beam energy show different caloric behaviors
and are discussed.Comment: 12 pages in Revtex including two Postscript figure
Web Browsing Behavior Analysis and Interactive Hypervideo
© ACM, 2013. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in, ACM Transactions on the Web, Vol. 7, No. 4, Article 20, Publication date: October 2013.http://doi.acm.org/ 10.1145/2529995.2529996[EN] Processing data on any sort of user interaction is well known to be cumbersome and mostly time consuming.
In order to assist researchers in easily inspecting fine-grained browsing data, current tools usually display
user interactions as mouse cursor tracks, a video-like visualization scheme. However, to date, traditional
online video inspection has not explored the full capabilities of hypermedia and interactive techniques.
In response to this need, we have developed SMT 2ǫ, a Web-based tracking system for analyzing browsing
behavior using feature-rich hypervideo visualizations. We compare our system to related work in academia
and the industry, showing that ours features unprecedented visualization capabilities. We also show that
SMT 2ǫ efficiently captures browsing data and is perceived by users to be both helpful and usable. A series of
prediction experiments illustrate that raw cursor data are accessible and can be easily handled, providing
evidence that the data can be used to construct and verify research hypotheses. Considering its limitations,
it is our hope that SMT 2ǫ will assist researchers, usability practitioners, and other professionals interested
in understanding how users browse the Web.This work was partially supported by the MIPRCV Consolider Ingenio 2010 program (CSD2007-00018) and the TIN2009-14103-C03-03 project. It is also supported by the 7th Framework Program of the European Commision (FP7/2007-13) under grant agreement No. 287576 (CasMaCat).Leiva Torres, LA.; VivĂł Hernando, RA. (2013). Web Browsing Behavior Analysis and Interactive Hypervideo. ACM Transactions on the Web. 7(4):20:1-20:28. https://doi.org/10.1145/2529995.2529996S20:120:287
A high-precision polarimeter
We have built a polarimeter in order to measure the electron beam
polarization in hall C at JLAB. Using a superconducting solenoid to drive the
pure-iron target foil into saturation, and a symmetrical setup to detect the
Moller electrons in coincidence, we achieve an accuracy of <1%. This sets a new
standard for Moller polarimeters.Comment: 17 pages, 9 figures, submitted to N.I.
Temperature determination from the lattice gas model
Determination of temperature from experimental data has become important in
searches for critical phenomena in heavy ion collisions. Widely used methods
are ratios of isotopes (which rely on chemical and thermal equilibrium),
population ratios of excited states etc. Using the lattice gas model we propose
a new observable: where is the charge multiplicity and
is the charge of the fragmenting system. We show that the reduced multiplicity
is a good measure of the average temperature of the fragmenting system.Comment: 11 pages, 2 ps file
An investigation of standard thermodynamic quantities as determined via models of nuclear multifragmentation
Both simple and sophisticated models are frequently used in an attempt to
understand how real nuclei breakup when subjected to large excitation energies,
a process known as nuclear multifragmentation. Many of these models assume
equilibriumthermodynamics and produce results often interpreted as evidence of
a phase transition. This work examines one class of models and employs standard
thermodynamical procedure to explore the possible existence and nature of a
phase transition. The role of various terms, e.g. Coulomb and surface energy,
is discussed.Comment: 19 two-column format pages with 24 figure
One-loop chiral amplitudes of Moller scattering process
The high energy amplitudes of the large angles Moller scattering are
calculated in frame of chiral basis in Born and 1-loop QED level. Taking into
account as well the contribution from emission of soft real photons the compact
relations free from infrared divergences are obtained. The expressions for
separate chiral amplitudes contribution to the cross section are in agreement
with renormalization group predictions.Comment: 15 pages, 3 figure
A model for nuclear matter fragmentation: phase diagram and cluster distributions
We develop a model in the framework of nuclear fragmentation at thermodynamic
equilibrium which can be mapped onto an Ising model with constant
magnetization. We work out the thermodynamic properties of the model as well as
the properties of the fragment size distributions. We show that two types of
phase transitions can be found for high density systems. They merge into a
unique transition at low density. An analysis of the critical exponents which
characterize observables for different densities in the thermodynamic limit
shows that these transitions look like continuous second order transitions.Comment: 27 pages, 5 figures; comments on microcanonical approach and other
minor corrections added; references added; 1 figure change
Weak evidence of bright light effects on human LH and FSH
<p>Abstract</p> <p>Background</p> <p>Most mammals are seasonal breeders whose gonads grow to anticipate reproduction in the spring and summer. As day length increases, secretion increases for two gonadotropins, luteinizing hormone (LH) and follicle stimulating hormone (FSH). This response is largely controlled by light. Light effects on gonadotropins are mediated through effects on the suprachiasmatic nucleus and responses of the circadian system. There is some evidence that seasonal breeding in humans is regulated by similar mechanisms, and that light stimulates LH secretion, but primate responses seem complex.</p> <p>Methods</p> <p>To gain further information on effects of bright light on LH and FSH secretion in humans, we analyzed urine samples collected in three experiments conducted for other goals. First, volunteers ages 18-30 years and 60-75 commenced an ultra-short 90-min sleep-wake cycle, during which they were exposed to 3000 lux light for 3 hours at balanced times of day, repeated for 3 days. Urine samples were assayed to explore any LH phase response curve. Second, depressed participants 60-79 years of age were treated with bright light or dim placebo light for 28 days, with measurements of urinary LH and FSH before and after treatment. Third, women of ages 20-45 years with premenstrual dysphoric disorder (PMDD) were treated to one 3-hour exposure of morning light, measuring LH and FSH in urine before and after the treatments.</p> <p>Results</p> <p>Two of the three studies showed significant increases in LH after light treatment, and FSH also tended to increase, but there were no significant contrasts with parallel placebo treatments and no significant time-of-day treatment effects.</p> <p>Conclusions</p> <p>These results gave some support for the hypothesis that bright light may augment LH secretion. Longer-duration studies may be needed to clarify the effects of light on human LH and FSH.</p
Microcanonical studies concerning the recent experimental evaluations of the nuclear caloric curve
The microcanonical multifragmentation model from [Al. H. Raduta and Ad. R.
Raduta, Phys. Rev. C 55, 1344 (1997); 56, 2059 (1997); 59, 323 (1999)] is
refined and improved by taking into account the experimental discrete levels
for fragments with and by including the stage of sequential decay of
the primary excited fragments. The caloric curve is reevaluated and the heat
capacity at constant volume curve is represented as a function of excitation
energy and temperature. The sequence of equilibrated sources formed in the
reactions studied by the ALADIN group (Au+Au at 600, 800 and
1000 MeV/nucleon bombarding energy) is deduced by fitting simultaneously the
model predicted mean multiplicity of intermediate mass fragments ()
and charge asymmetry of the two largest fragments () versus bound
charge () on the corresponding experimental data. Calculated HeLi
isotopic temperature curves as a function of the bound charge are compared with
the experimentally deduced ones.Comment: 13 pages, 4 figure
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